Osteochondroma

  • What is osteochondroma?

    Osteochondroma is one of the most common benign bone tumors in children, yet it is also one of the most silent. Because osteochondromas often display no symptoms, the tumors are generally only discovered when another problem is diagnosed. For many children, the tumors are never discovered.

    Osteochondromas look like a bony projection on the external surface of a bone, like a bony mushroom on a stalk, usually near a growth plate. It can occur in any bone but is seen most often around the knee or the upper arm.

    These tumors generally stop growing once a child stops growing. Most are found in patients younger than 20 years old and more often in boys.

    Osteochondromas are classified by stages and most of these tumors are stage I or II:

    • Stage I — tumors are no longer growing
    • Stage II — actively growing tumors
    • Stage III — actively growing tumors that are causing destruction to the area
  • Causes

    It is unknown what causes osteochondromas. However, there is a theory these tumors may be the result of genetic abnormalities. Clinicians at The Children’s Hospital of Philadelphia are conducting research into this condition and its origins.

  • Signs and symptoms

    Usually these tumors cause no symptoms. However, depending of the location of the osteochondroma, some tumors can grow and cause symptoms including:

    • Pain
    • Deformity
    • Growth disturbances
    • Mechanical difficulties
  • Testing and diagnosis

    At The Children’s Hospital of Philadelphia, our clinical experts use a variety of diagnostic tests to diagnose osteochondroma in children, including:

    • X-rays, which produce images of bones on film.
    • Radioisotope bone scan, which can help locate an area of abnormal bone growth. 
    • Magnetic resonance imaging (MRI), which uses a combination of large magnets, radiofrequencies and a computer to produce detailed images of organs and structures within the body.
    • Computed tomography (CT) scan, which uses a combination of X-rays and computer technology to produce cross-sectional images ("slices") of the body.
    • EOS imaging, an imaging technology that creates 3-dimensional models from two planar images. Unlike a CT scan, EOS images are taken while the child is in an upright or standing position, enabling improved diagnosis due to weight-bearing positioning.

    In addition to imaging tests, your child's doctor may recommend a biopsy to confirm the diagnosis of osteochondroma. A biopsy is a short procedure where a sample of the growth is surgically removed and then tested for malignant and benign cells.

    Your child's doctor will examine the tumor carefully to be sure it is not another type of tumor, such as a chondrosarcoma, which is cancerous.

  • Treatments

    If your child’s osteochondroma is fast-growing or affecting growth alignment, surgery may be necessary.

    Treatment for osteochondroma is generally an en bloc resection, which is surgical removal of the entire growth and areas around the tumor. The tumor must be completely removed, leaving no remnants behind to ensure the tumor does not recur. The surgeon will be extremely careful not to harm the growth plate to ensure your child’s normal physical development after the operation.

    Though surgery for osteochondroma is highly effective, we understand that any surgery can be a stressful experience for your child and family. At CHOP, we offer a wealth of resources about how to prepare your child for surgery and what to expect during surgery.

    Additionally, we employ numerous best practices before, during and after surgery to decrease the risk of infection and increase positive outcomes. See safety in surgery for details about safety protocols at The Children's Hospital of Philadelphia.

  • Follow-up care

    After surgery for osteochondroma, most children can resume normal activities. However, in some cases, where the tumor was on a weight-bearing bone, your child’s physician may recommend restricted activity for your child to allow proper healing.

    If the tumor caused no bone deformity or compromise of the growth plate, your child should follow-up with the doctor only if needed. If there are complications, your child should see a physician regularly to continue monitoring the condition.

    Follow-up care and ongoing support and services are available at our Main Campus and throughout our CHOP Care Network. Our team is committed to partnering with parents and referring physicians to provide the most current, comprehensive and specialized care possible for your child.

  • Outlook

    There is a 2-5 percent chance an osteochondroma will recur. The outcome and prognosis for osteochondromas after surgery is excellent.

    In some cases, children with osteochondroma can develop hereditary multiple osteochondromas (HMO), previously called hereditary multiple exostoses (HME). The disorder is characterized by multiple osteochondroma growths and is inherited from one parent in 90 percent of cases. Because these genetic mutations run in families, it is advisable to have any siblings of the child with HMO examined by experienced medical professionals.

Reviewed by John P. Dormans, MD, FACS on May 19, 2014